The medicinal uses of natural products obtained from various plants are well known for a long time now. The medicinal uses of these natural products offer several benefits. For example, these natural products do not cause any relevant side effects. Therefore, in order to exploit the medicinal applicability of these natural products, efforts have been made to extract different pharmacologically active ingredients from various plants. Accordingly, several methods of extraction of pharmacologically active ingredients from various plants exist in the art.
Pharmacologically active ingredients are secondary metabolites of a plant that are usually present deep inside the tissues of the plant. Usually, production of the secondary metabolites in a plant is often very low. Generally, pharmacologically active ingredients of a plant constitute less than 1% of the total weight of the plant (weight taken as a dry plant). In addition, the percentage of pharmacologically active ingredients in a plant depends on physiological and developmental stage of the plant. For example, an immature plant yields lesser percentage of pharmacologically active ingredients as compared to a matured plant. Further, since the secondary metabolites exist deep inside the tissues of a plant, penetration of an extraction solvent deep into the tissues of the plant becomes important. Therefore, these critical factors need to be considered for developing extraction processes for obtaining fractions containing optimum quantities of pharmacologically active ingredients.
The existing methods for extracting pharmacologically active ingredients from various plants yield fractions containing desired pharmacologically active ingredients along with undesired pharmacologically active ingredients in a sufficient amount to cause cytotoxicity. In addition, the fractions containing desired pharmacologically active ingredients may contain a certain amount of pigments and lipids, which may render cytotoxicity to the fractions containing desired pharmacologically active ingredients either directly or indirectly by co-association with other cytotoxic agents.
Therefore, there is a need in the art for a method of extracting fractions containing desired pharmacologically active ingredients, wherein the fractions are less cytotoxicity and are therapeutically more effective in various diseases as compared to corresponding fractions obtained using conventional methods.